LibGuides: Searching: Block search

Block search

Block search is a method to structure your search. You need to use a search tool that understands boolean operators and preferably allows you to use different lines for searching (i.e. a bibliographic database).

Step 1. Identify the different concepts that you would like your search results to include.

Examples:

Research question	Concepts
Does climate change effect bird migration?	"climate change", bird, migration
Is mycorrhiza effected by clearcutting in boreal forests?	clearcutting, "boreal forest", mycorrhiza
How does bacteria interact with myeloid cells to manipulate their function?	bacteria, "myeloid cells", manipulation
Is aquatic biodiversity affected by climate change?	aquatic, biodiversity, "climate change"

Step 2. Put the different concepts on different lines (=blocks) with AND in between.

If you can't see the different lines you may have to go to "advanced search". Example:

Block 1	aquatic
	AND
Block 2	biodiversity
	AND
Block 3	"climate change"

In the search tool, it may look something like this:

Step 3. Add synonyms, alternative expressions, spelling variants etc. on each line/block with OR.

Don't forget truncation and phrase search! Example:

Block 1	*aquatic OR lake OR limn OR marine OR ocean OR freshwater OR river**
	AND
Block 2	biodiversity OR diversity OR "genetic variation" OR "species richness"
	AND
Block 3	"climate change" OR "global change" OR "global warming" OR "greenhouse effect"

Structuring your search like this is a way of telling the search tool that you want all results to include at least one thing from block 1, at least one thing from block 2 and at least one thing from block 3.

General tips

An alternative to using lines is to put each "line" within parentheses. However, when doing advanced searches it is easy to put a single parenthesis wrong which will mess up your whole search. We suggest you stick with the lines if you can (however not all search tools have the option of lines). Example:

(cat OR feline) AND (behavior OR behaviour OR etology)

If you get strange results it is likely that you have forgotten a boolean operator. For example, if you search for

(cat OR feline) AND (behavior OR behaviour etology) forgot an "OR" between behaviour and etology

What you are really searching for is:

(cat OR feline) AND (behavior OR behaviour AND etology), which means that etology must be in all results, reducing the result list dramatically.